Structural and thermal characterization of ternary complexes of piroxicam and alanine with transition metals: uranyl binary and ternary complexes of piroxicam. Spectroscopic characterization and properties of metal complexes

Ternary Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO2(II) complexes with piroxicam (Pir) drug (H2L1) and dl-alanine (Ala) (HL2) and also the binary UO2(II) complex with Pir were studied. The structures of the complexes were elucidated using elemental, IR, molar conductance, magnetic moment, diffused reflectance and thermal analyses. The UO2(II) binary complex was isolated in 1:2 ratio with the formula [UO2(H2L)2](NO3)2. The ternary complexes were isolated in 1:1:1 (M:H2L1:L2) ratios. The solid complexes were isolated in the general formulae [M(H2L)(L2)(Cl)n(H2O)m].yH2O (M=Fe(III) (n=2, m=0, y=1), Co(II) (n=1, m=1, y=2) and Ni(II) (n=1, m=1, y=0)); [M(H2L)(L2)](X)z.yH2O (M=Cu(II) (X=AcO, z=1, y=0), Zn(II) (X=AcO, z=1, y=3) and UO2(II) (X=NO3, z=1, y=2)). Pir behaves as a neutral bidentate ligand coordinated to the metal ions via the pyridine-N and carbonyl-O groups, while Ala behaves as a uninegatively bidentate ligand coordinated to the metal ions via the deprotonated carboxylate-O and amino-N. The magnetic and reflectance spectral data show that the complexes have octahedral geometry except Cu(II) and Zn(II) complexes have tetrahedral structures. The thermal decomposition of the complexes was discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated.     

Potentiometric, spectroscopic and thermal studies on the metal chelates of 1-(2-thiazolylazo)-2-naphthalenol

The synthesis and characterization of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pd(II) and UO2(II) chelates of 1-(2-thiazolylazo)-2-naphthalenol (TAN) were reported. The dissociation constants of the ligand and the stability constants of the metal complexes were calculated pH-metrically at 25 degrees C and 0.1 M ionic strength. The solid complexes were characterized by elemental and thermal analyses, molar conductance, IR, magnetic and diffuse reflectance spectra. The complexes were found to have the formulae [M(L)2] for M = Mn(II), Co(II), Ni(II), Zn(II) and Cd(II); [M(L)X].nH2O for M = Cu(II) (X = AcO, n = 3), Pd(II) (X = Cl, n = 0) and UO2(II) (X = NO3, n = 0), and [Fe(L)Cl2(H2O)].2H2O. The molar conductance data reveal that the chelates are non-electrolytes. IR spectra show that the ligand is coordinated to the metal ions in a terdentate manner with ONN donor sites of the naphthyl OH, azo N and thiazole N. An octahedral structure is proposed for Mn(II), Fe(III), Co(II), Ni(II), Zn(II), Cd(II) and UO2(II) complexes and a square planar structure for Cu(II) and Pd(II) complexes. The thermal behaviour of these chelates shows that water molecules (coordinated and hydrated) and anions are removed in two successive steps followed immediately by decomposition of the ligand molecule in the subsequent steps. The relative thermal stability of the chelates is evaluated. The final decomposition products are found to be the corresponding metal oxides. The thermodynamic activation parameters, such as E*, delta H*, delta S* and delta G* are calculated from the TG curves.     

Structural and thermal characterization of cerium, thorium and uranyl complexes of sulfasalazine

Cerium(IV), Thorium(IV) and Uranyl(II) complexes with the ammonium salt of sulfasalazine drug (H2SSZ, HL-) have been studied. The structures of the complexes were elucidated using elemental analysis, IR and mass spectroscopy and thermal analysis. The complexes were isolated in 1:1 and 1:2 (M:L) ratios. The solid monocomplexes (1:1) (M:H(2)SSZ) were isolated in the general formulae [UO2(L)(H2O)2].2H2O and [M(L)(X)z(H2O)n].yH2O (M=Ce(IV) and Th(IV) (X=NO3, z=2, n=2, y=0-3)). The biscomplexes (1:2) (M:H2SSZ) solid chelates found to have the general formulae [UO2(HL)2].2H2O and [M(L)2(H2O)2] (M=Ce(IV) and Th(IV)). The thermal decomposition of the complexes should be discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated applying Coats-Redfern and Horwitz-Mitzger methods.     

Structural, spectroscopic and thermal characterization of 2-tert-butylaminomethylpyridine-6-carboxylic acid methylester and its Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO(2)(II) complexes

Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO(2)(II) complexes with the ligand 2-tert-butylaminomethylpyridine-6-carboxylic acid methylester (HL(2)) have been prepared and characterized by elemental analyses, molar conductance, magnetic moment, thermal analysis and spectral data. 1:1 M:HL(2) complexes, with the general formula [M(HL(2))X(2)].nH(2)O (where M = Co(II) (X = Cl, n = 0), Ni(II) (X = Cl, n = 3), Cu(II) (grey colour, X = AcO, n = 1), Cu(II) (yellow colour, X = Cl, n = 0) and Zn(II) (X = Br, n = 0). In addition, the Fe(III) and UO(2)(II) complexes of the type 1:2 M:HL(2) and with the formulae [Fe(L(2))(2)]Cl and [UO(2)(HL(2))(2)](NO(3))(2) are prepared. From the IR data, it is seen that HL(2) ligand behaves as a terdentate ligand coordinated to the metal ions via the pyridyl N, carboxylate O and protonated NH group; except the Fe(III) complex, it coordinates via the deprotonated NH group. This is supported by the molar conductance data, which show that all the complexes are non-electrolytes, while the Fe(III) and UO(2)(II) complexes are 1:1 electrolytes. IR and H1-NMR spectral studies suggest a similar behaviour of the Zn(II) complex in solid and solution states. From the solid reflectance spectral data and magnetic moment measurements, the complexes have a trigonal bipyramidal (Co(II), Ni(II), Cu(II) and Zn(II) complexes) and octahedral (Fe(III), UO(2)(II) complexes) geometrical structures. The thermal behaviour of the complexes is studied and the different dynamic parameters are calculated applying Coats-Redfern equation.     

Synthesis, characterization and biological activity of some transition metals with Schiff base derived from 2-thiophene carboxaldehyde and aminobenzoic acid

Metal complexes of Schiff base derived from 2-thiophene carboxaldehyde and 2-aminobenzoic acid (HL) are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analysis (TGA). The ligand dissociation as well as the metal-ligand stability constants were calculated pH metrically at 25 degrees C and ionic strength mu=0.1 (1M NaCl). The complexes are found to have the formulae [M(HL)2](X)n.yH2O (where M=Fe(III) (X=Cl, n=3, y=3), Co(II) (X=Cl, n=2, y=1.5), Ni(II) (X=Cl, n=2, y=1) and UO2(II) (X=NO3, n=2, y=0)) and [M(L)2] (where M=Cu(II) (X=Cl) and Zn(II) (X=AcO)). The molar conductance data reveal that Fe(III) and Co(II), Ni(II) and UO2(II) chelates are ionic in nature and are of the type 3:1 and 2:1 electrolytes, respectively, while Cu(II) and Zn(II) complexes are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a terdentate manner with ONS donor sites of the carboxylate O, azomethine N and thiophene S. From the magnetic and solid reflectance spectra, it is found that the geometrical structure of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, DeltaH*, DeltaS* and DeltaG* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species.     

Structure investigation, spectral, thermal, X-ray and mass characterization of piroxicam and its metal complexes

[M(H2L)2](A)2.yH2O (where H2L: neutral piroxicam (Pir), A: Cl- in case of Ni(II) or acetate anion in case of Cu(II) and Zn(II) ions and y=0-2.5) and [M(H2L)3](A)z.yH2O (A: SO4(2-) in case of Fe(II) ion (z=1) or Cl(-) in case of Fe(III) (z=3) and Co(II) ions (z=2) and y=1-4) chelates are prepared and characterized using elemental analyses, IR, magnetic and electronic reflectance measurements, mass spectra and thermal analyses. IR spectra reveal that Pir behaves a neutral bidentate ligand coordinated to the metal ions through the pyridyl-N and carbonyl-O of the amide moiety. The reflectance and magnetic moment measurements reveal that these chelates have tetrahedral, square planar and octahedral geometrical structures. Mass spectra and thermal analyses are also used to confirm the proposed formulae and the possible fragments resulted from fragmentation of Pir and its chelates. The thermal behaviour of the chelates (TGA and DTA) are discussed in detail and the thermal stability of the anhydrous chelates follow the order Ni(II) congruent with Cu(II) Fe(II)相似文献   

Synthesis, characterization and thermal studies on metal complexes of new azo compounds derived from sulfa drugs

Four new azo ligands, L1 and HL2-4, of sulfa drugs have been prepared and characterized. [MX(2)(L1)(H(2)O)(m)].nH(2)O; [(MX(2))(2)(HL2 or HL3)(H(2)O)(m)].nH(2)O and [M(2)X(3)(L4)(H(2)O)].nH(2)O; M=Co(II), Ni(II) and Cu(II) (X=Cl) and Zn(II) (X=AcO); m=0-4 and n=0-3, complexes were prepared. Elemental and thermal analyses (TGA and DTA), IR, solid reflectance spectra, magnetic moment and molar conductance measurements have accomplished characterization of the complexes. The IR data reveal that HL1 and HL2-3 ligands behave as a bidentate neutral ligands while HL4 ligand behaves as a bidentate monoionic ligand. They coordinated to the metal ions via the carbonyl O, enolic sulfonamide S(O)OH, pyrazole or thiazole N and azo N groups. The molar conductance data reveal that the chelates are non-electrolytes. From the solid reflectance spectra and magnetic moment data, the complexes were found to have octahedral, tetrahedral and square planar geometrical structures. The thermal behaviour of these chelates shows that the water molecules (hydrated and coordinated) and the anions are removed in a successive two steps followed immediately by decomposition of the ligand in the subsequent steps. The activation thermodynamic parameters, such as, E*, DeltaH*, DeltaS* and DeltaG* are calculated from the TG curves applying Coats-Redfern method.     

Preparation, characterization and biological activity of Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) complexes of new cyclodiphosph(V)azane of sulfaguanidine

Novel hexachlorocyclodiphosph(V)azane of sulfaguanidine, H(4)L, l,3-[N'-amidino-sulfanilamide]-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane was prepared and its coordination behaviour towards the transition metal ions Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV-vis, (1)H NMR, mass spectra, reflectance, magnetic susceptibility measurements and thermogravimetric analysis (TGA). The hyperfine interactions in the isolated complex compounds were studied using 14.4keV gamma-ray from radioactive (57)Co (M?ssbauer spectroscopy). The data show that the ligand are coordinated to the metal ions via the sulfonamide O and deprotonated NH atoms in an octahedral manner. The H(4)L ligand forms complexes of the general formulae [(MX(z))(2)(H(2)L)H(2)O)(n)] and [(FeSO(4))(2) (H(4)L) (H(2)O)(4)], where X=NO(3) in case of UO(2)(II) and Cl in case of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The molar conductance data show that the complexes are non-electrolytes. The thermal behaviour of the complexes was studied and different thermodynamic parameters were calculated using Coats-Redfern method. Most of the prepared complexes showed high bactericidal activity and some of the complexes show more activity compared with the ligand and standards.     

Metal complexes of Schiff base derived from sulphametrole and o-vanilin. Synthesis, spectral, thermal characterization and biological activity

Metal complexes of Schiff base derived from condensation of o-vanilin (3-methoxysalicylaldehyde) and sulfametrole [N(1)-(4-methoxy-1,2,5-thiadiazole-3-yl)sulfanilamide] (H2L) are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, mass spectra, UV-vis and thermal analysis (TGA). From the elemental analyses data, the complexes were proposed to have the general formulae [M2X3(HL)(H2O)5].yH2O (where M=Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), X=Cl, y=0-3); [Fe2Cl5(HL)(H2O)3].2H2O; [(FeSO4)2(H2L)(H2O)4] and [(UO2)2(NO3)3(HL)(H2O)].2H2O. The molar conductance data reveal that all the metal chelates were non-electrolytes. The IR spectra show that, H2L is coordinated to the metal ions in a tetradentate manner with ON and NO donor sites of the azomethine-N, phenolic-OH, enolic sulphonamide-OH and thiadiazole-N. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, DeltaH*, DeltaS* and DeltaG* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligand, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia coli, Salmonella typhi, Bacillus subtillus, Staphylococcus aureus and Fungi (Aspergillus terreus and Aspergillus flavus). The activity data show that the metal complexes to be more potent/antimicrobial than the parent Shciff base ligand against one or more microbial species.     

Site specificity of metal ions in heterodinuclear complexes derived from an "end-off" compartmental ligand

A phenol-based "end-off" compartmental ligand, 2-[N-[2-(dimethylamino)ethyl]iminomethyl]-6-[N,N-di(2-pyridylmethyl)aminomethyl]-4-methylphenol (HL), having a bidentate arm and a tridentate arm attached to the 2 and 6 positions of the phenolic ring, has afforded the following heterodinuclear M(a)(II)M(b)(II) complexes: [CuM(L)(AcO)(2)]ClO(4) (M = Mn (1), Fe (2), Co (3), Ni (4), Zn (5)), [ZnM(L)(AcO)(2)]ClO(4) (M = Co (6), Ni (7)), and [CuNi(L)(AcO)(NCS)(2)] (8). 1.MeOH (1'), 2.MeOH (2'), 3.MeOH (3'), 4.MeOH (4'), 5.MeOH (5'), and 7.MeOH (7') are isostructural and have a heterodinuclear core bridged by the phenolic oxygen atom of L(-) and two acetate groups. In 1'-5' the Cu(II) is bound to the bidentate arm and has a square-pyramidal geometry with one acetate oxygen at the apical site. The M(II) is bound to the tridentate arm and has a six-coordinate geometry together with two acetate oxygen atoms. In the case of 7' the Zn is bound to the bidentate arm and the Ni is bound to the tridentate arm. 8.2-PrOH (8') has a dinuclear core bridged by the phenolic oxygen atom of L(-) and one acetate group. The Cu bound to the bidentate arm has a square-pyramidal geometry with an isothiocyanate group at the apical site. The Ni bound to the tridentate arm has a six-coordinate geometry with further coordination of an isothiocyanate group. The site specificity of the metal ions is discussed together with the crystal structure of [Cu(4)(L)(2)(AcO)(3)](ClO(4))(3).H(2)O (9) prepared in this work.     

Synthesis, spectroscopic, thermal and antimicrobial studies of some novel metal complexes of Schiff base derived from [N1-(4-methoxy-1,2,5-thiadiazol-3-yl)sulfanilamide] and 2-thiophene carboxaldehyde

Keeping in view the chemotherapeutic of the sulfa-drugs, Schiff base namely 2-thiophene carboxaldehyde-sulfametrole (HL) and its tri-positive and di-positive metal complexes have been synthesized and characterized by elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, mass spectra, UV-vis and thermal analysis (TGA and DrTG). The low molar conductance values suggest the non-electrolytic nature of these complexes. IR spectra show that HL is coordinated to the metal ions in a tetradentate manner through hetero five-membered ring-S and azomethine-N, enolic sulfonamide-OH and thiadiazole-N, respectively. Zn(II), Cd(II) and UO2(II) complexes are found to be diamagnetic (as expected). The proposed general formulae of the prepared complexes are [M2X4(HL)(H2O)4] (where M=Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), X=Cl, [Fe2Cl6(HL)(H2O)2], [(FeSO4)2(HL)(H2O)4] and [(UO2)2(HL) (NO3)4].H2O. The thermal behaviour of these chelates shows that the hydrated complexes loss water of hydration in first step in case of uranium complexes followed loss coordinated water followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as DeltaE*, DeltaH*, DeltaS*, and DeltaG* are calculated from the DrTG curves using Coats-Redfern method. The antimicrobial activity of the obtained products was performed using Chloramphenicol and Grisofluvine as standards, indicate that in some cases metallation increase activity than the ligand.     

Solvent control: dinuclear versus tetranuclear complexes of a bis-tetradentate pyrimidine-based ligand

A new bis-tetradentate acyclic amine ligand L(Et) has been synthesized from 4,6-bis(aminomethyl)-2-phenylpyrimidine and 2-vinylpyridine. Dinuclear complexes, Mn(II)(2)L(Et)(MeCN)(H(2)O)(3)(ClO(4))(4) (1), Fe(II)(2)L(Et)(H(2)O)(4)(BF(4))(4) (2), Co(II)(2)L(Et)(H(2)O)(3)(MeCN)(2)(BF(4))(4) (3), Ni(II)(2)L(Et)(H(2)O)(4)(BF(4))(4) (4), Ni(II)(2)L(Et)(H(2)O)(4)(ClO(4))(4)·8H(2)O (4'), Cu(II)(2)L(Et)(BF(4))(4)·MeCN (5), Zn(II)(2)L(Et)(BF(4))(2)(BF(4))(2)·?MeCN (6), were obtained from 1 : 2 reactions of L(Et) and the appropriate metal salts in MeCN, whereas in MeOH tetranuclear complexes, Mn(II)(4)(L(Et))(2)(OH)(4)(ClO(4))(4) (7), Fe(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·5/2H(2)O (8), Co(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·3H(2)O (9), Ni(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·4H(2)O (10), Cu(II)(4)(L(Et))(2)(F)(4)(BF(4))(4)·3H(2)O (11) and Zn(II)(4)(L(Et))(2)(F)(4)(BF(4))(4) (12), result. Six complexes have been structurally characterized: in all cases each L(Et) is bis-tetradentate and provides a pyrimidine bridge between two metal centres. As originally anticipated, complexes 1, 4' and 6 are dinuclear, while 9, 10 and 12 are revealed to be tetranuclear, with two M(2)(L(Et))(4+) moieties bridged by two pairs of fluoride anions. Weak to moderate antiferromagnetic coupling between the metal centres is a feature of complexes 2, 3, 4, 8, 9 and 10. The dinuclear complexes 1-6 undergo multiple, mostly irreversible, redox processes. However, the pyrimidine-based dicopper(II) complex 5 undergoes a two electron quasi-reversible reduction, Cu(II)(2)→ Cu(I)(2), and this occurs at a more positive potential [E(m) = +0.11 V (E(pc) = -0.03 and E(pa) = +0.26 V) vs. 0.01 M AgNO(3)/Ag] than for either of the dicopper(II) complexes of the analogous pyrazine-based ligands.     

Synthesis and thermal characterization of new ternary chelates of piroxicam and tenoxicam with glycine and DL-phenylalanine and some transition metals

The ternary chelates of piroxicam (Pir) and tenoxicam (Ten) with Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) in the presence of various amino acids such as glycine (Gly) or dl-phenylalanine (PhA) were prepared and characterized with different physicochemical methods. IR spectra confirm that Pir and Ten behave as a neutral bidentate ligand coordinated to the metal ions via the pyridine-N and carbonyl group of the amide moiety. Gly molecule acted as a uninegatively monodentate ligand and coordinate to the metal ions through its deprotonated carboxylic group. In addition, PhA acted as a uninegatively bidentate ligand and coordinate to the metal ions through its deprotonated carboxylic and amino groups. The solid reflectance spectra and magnetic moment measurements confirm that all the chelates have octahedral geometrical structures while Cu(II)- and Zn(II)-ternary chelates with PhA have square planar geometrical structures. Thermal behaviour of the complexes is extensively studied using TG and DTA techniques. TG results show that water molecules (hydrated and coordinated) and anions are removed in the first and second steps while Gly, PhA, Pir and Ten are decomposed in the next and subsequent steps. The pyrolyses of the chelates into different gases are observed in the DTA curves as exo- or endothermic peaks. Also, phase transition states are observed in some chelates. Different thermodynamic parameters are calculated using Coats-Redfern method and the results are interpreted.     

Separation and spectroscopic characterization of new metal chelates of 8-arylazo-6-formyl-7-hydroxy-5-methoxy-2-methyl chromones

Transition metal chelates of the title compounds have been prepared and characterized by elemental analyses, i.r., 1H-n.m.r., electronic spectra, thermogravimetric analysis, conductometric and magnetic measurements. Chelates of general formulae MLjX · nH2O for 1:1 (M:L), where X=OH– or Cl–, j=1 or 2, n=1– 4 and M=VO2+, Cr3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+ ions or ML2 for 1:2 (M:L) Ni-(1a), ML2·2H2O where M=Co2+, Ni2+ and Cu2+ or M2LjX·nH2O for 2:1 (M:L) Cr3+, Fe2+, Ni2+ and Cu2+, L=Ligand, have been prepared. I.r. and 1H-n.m.r. spectra indicate that the aldehydic group in position six and the hydroxylic group in position seven are involved in chelation in the 1:1 and 1:2 (M:L) chelates, whereas for 2:1 (M:L) chelates with (1c), the interaction of the metal ion takes place through CHO, OH, CO2H and NN groups. Tetrahedral, octahedral and square planar geometries are proposed for the chelates based on their electronic spectra and magnetic moments.     

Neutral (bis-beta-diketonato) iron(III), cobalt(II), nickel(II), copper(II) and zinc(II) metallocycles: structural, electrochemical and solvent extraction studies

Neutral dimeric metallocyclic complexes of type [M(2)(L(1))(2)B(n)] (where M = cobalt(II), nickel(II) and zinc(II), L(1) is the doubly deprotonated form of a 1,3-aryl linked bis-beta-diketone ligand of type 1,3-bis(RC(O)CH(2)C(O))C(6)H(4) (R=Me, n-Pr, t-Bu) and B is pyridine (Py) or 4-ethylpyridine (EtPy)) have been synthesised, adding to similar complexes already reported for copper(II). New lipophilic ligand derivatives with R = octyl or nonyl were also prepared for use in solvent extraction experiments. Structural, electrochemical and solvent extraction investigations of selected metal complex systems from the above series are reported, with the X-ray structures of [Co(2)(L(1))(2)(Py)(4)] x 2.25CHCl(3) x 0.5H(2)O (R=Pr), [Co(2)(L(1))(2)(EtPy)(4)] (R=t-Bu), [Ni(2)(L(1))(2)(EtPy)(4)] (R=t-Bu), [Zn(2)(L(1))(2)(EtPy)(2)] (R=Me) and [Zn(2)(L(1))(2)(EtPy)(4)] (R=t-Bu) being presented. The electrochemistry of H(2)L(1) (R=t-Bu) and of [Fe(2)(L(1))(3)], [Co(2)(L(1))(2)(Py)(4)], [Ni(2)(L(1))(2)(Py)(4)], [Cu(2)(L(1))(2)] and [Zn(2)(L(1))(2)(Py)(2)] has been examined. Oxidative processes for the complexes are dominantly irreversible, but several examples of quasireversible behaviour were observed and support the assignment of an anodic process, seen between +1.0 and +1.6 V, as a metal-centred oxidation. The reduction processes for the respective metal complexes are not simple, and irreversible in most cases. Solvent extraction studies (water/chloroform) involving variable concentrations of metal, bis-beta-diketone and heterocyclic base have been performed for cobalt(II) and zinc(II) using a radiotracer technique to probe the stoichiometries of the extracted species in each case. Synergism was observed when 4-ethylpyridine was added to the bis-beta-diketone ligand in the chloroform phase. Competitive extraction studies show a clear uptake preference for copper(II) over cobalt(II), nickel(II), zinc(II) and cadmium(II).     

Electronic structures of ruthenium and osmium complexes of 9,10-phenanthrenequinone

The reaction of 9,10-phenanthrenequinone (PQ) with [M(II)(H)(CO)(X)(PPh(3))(3)] in boiling toluene leads to the homolytic cleavage of the M(II)-H bond, affording the paramagnetic trans-[M(PQ)(PPh(3))(2)(CO)X] (M = Ru, X = Cl, 1; M = Os, X = Br, 3) and cis-[M(PQ)(PPh(3))(2)(CO)X] (M = Ru, X = Cl, 2; M = Os, X = Br, 4) complexes. Single-crystal X-ray structure determinations of 1, 2·toluene, and 4·CH(2)Cl(2), EPR spectra, and density functional theory (DFT) calculations have substantiated that 1-4 are 9,10-phenanthrenesemiquinone radical (PQ(?-)) complexes of ruthenium(II) and osmium(II) and are defined as trans-[Ru(II)(PQ(?-))(PPh(3))(2)(CO)Cl] (1), cis-[Ru(II)(PQ(?-))(PPh(3))(2)(CO)Cl] (2), trans-[Os(II)(PQ(?-))(PPh(3))(2)(CO) Br] (3), and cis-[Os(II)(PQ(?-))(PPh(3))(2)(CO)Br] (4). Two comparatively longer C-O [average lengths: 1, 1.291(3) ?; 2·toluene, 1.281(5) ?; 4·CH(2)Cl(2), 1.300(8) ?] and shorter C-C lengths [1, 1.418(5) ?; 2·toluene, 1.439(6) ?; 4·CH(2)Cl(2), 1.434(9) ?] of the OO chelates are consistent with the presence of a reduced PQ(?-) ligand in 1-4. A minor contribution of the alternate resonance form, trans- or cis-[M(I)(PQ)(PPh(3))(2)(CO)X], of 1-4 has been predicted by the anisotropic X- and Q-band electron paramagnetic resonance spectra of the frozen glasses of the complexes at 25 K and unrestricted DFT calculations on 1, trans-[Ru(PQ)(PMe(3))(2)(CO)Cl] (5), cis-[Ru(PQ)(PMe(3))(2)(CO)Cl] (6), and cis-[Os(PQ)(PMe(3))(2)(CO)Br] (7). However, no thermodynamic equilibria between [M(II)(PQ(?-))(PPh(3))(2)(CO)X] and [M(I)(PQ)(PPh(3))(2)(CO)X] tautomers have been detected. 1-4 undergo one-electron oxidation at -0.06, -0.05, 0.03, and -0.03 V versus a ferrocenium/ferrocene, Fc(+)/Fc, couple because of the formation of PQ complexes as trans-[Ru(II)(PQ)(PPh(3))(2)(CO)Cl](+) (1(+)), cis-[Ru(II)(PQ)(PPh(3))(2)(CO)Cl](+) (2(+)), trans-[Os(II)(PQ)(PPh(3))(2)(CO)Br](+) (3(+)), and cis-[Os(II)(PQ)(PPh(3))(2)(CO)Br](+) (4(+)). The trans isomers 1 and 3 also undergo one-electron reduction at -1.11 and -0.96 V, forming PQ(2-) complexes trans-[Ru(II)(PQ(2-))(PPh(3))(2)(CO)Cl](-) (1(-)) and trans-[Os(II)(PQ(2-))(PPh(3))(2)(CO)Br](-) (3(-)). Oxidation of 1 by I(2) affords diamagnetic 1(+)I(3)(-) in low yields. Bond parameters of 1(+)I(3)(-) [C-O, 1.256(3) and 1.258(3) ?; C-C, 1.482(3) ?] are consistent with ligand oxidation, yielding a coordinated PQ ligand. Origins of UV-vis/near-IR absorption features of 1-4 and the electrogenerated species have been investigated by spectroelectrochemical measurements and time-dependent DFT calculations on 5, 6, 5(+), and 5(-).     

The use of IR, magnetism, reflectance, and mass spectra together with thermal analyses in structure investigation of codeine phosphate complexes of d-block elements

Codeine is an analgesic with uses similar to morphines, but it is of much less effect, i.e., it had a mild sedative effect; codeine is usually used as the phosphate form (Cod.P) and is often administrated by mouth with aspirin of paracetamol. Due to its serious use, if it is in large dose, attention is paid in this research to the synthesis and stereochemistry of new iron, cobalt, nickel, copper, and zinc complexes of this drug in both solution and the solid states. The spectra of these complexes in solution and the study of their stoichiometry refer to the formation of 1:1 ratio of metal (M) to ligand (L). The steriochemical structures of the solid complexes were studied on the basis of their analytical, spectroscopic, magnetic, and thermal data. Infrared spectra proved the presence of MO bonds. Magnetic susceptibility and solid reflectance spectral measurements were used to infer the structures. The prepared complexes were found to have the general formulae [ML(OH)(x)(H2O)(y)](H2O)(z)H3PO4, M: Co(II), Ni(II), and Cu(II), x = 1, y = 0, z = 0; M: Fe(II), x = 1, y = 2, z = 1; Fe(III), x = 2, y = 1, z = 0; Co(III), x = 0, y = 2, z = 1; Zn(II), x = 1, y = 0, z = 3; and L: (Cod.P) of the general formula C18H24NO7P (anhydrate). Octahedral, tetrahedral, and square planer structures were proposed for these complexes depending upon the magnetic and reflectance data and were confirmed by detailed mass and thermal analyses comparative studies.     

Synthesis and coordination chemistry of two N2-donor chelating di(indazolyl)methane ligands: structural characterization and comparison of their metal chelation aptitudes

The N(2)-donor bidentate ligands di(1H-indazol-1-yl)methane (L(1)) and di(2H-indazol-2-yl)methane (L(2)) (L in general) have been synthesized, and their coordination behavior toward Zn(II), Cd(II), and Hg(II) salts has been studied. Reaction of L(1) and L(2) with ZnX(2) (X = Cl, Br, or I) yields [ZnX(2)L] species (1-6), that, in the solid state, show a tetrahedral structure with dihapto ligand coordination via the pyrazolyl arms. The reaction of L(1) and L(2) with Zn(NO(3))(2)·6H(2)O is strongly dependent on the reaction conditions and on the ligand employed. Reaction of L(1) with equimolar quantities of Zn(NO(3))(2)·6H(2)O yields the neutral six-coordinate species [Zn(NO(3))(2)(L(1))], 7. On the other hand the use of L(1) excess gives the 2:1 adduct [Zn(NO(3))(2)(L(1))(2)], 8 where both nitrates act as a unidentate coordinating ligand. Analogous stoichiometry is found in the compound obtained from the reaction of L(2) with Zn(NO(3))(2)·6H(2)O which gives the ionic [Zn(NO(3))(L(2))(2)](NO(3)), 10. Complete displacement of both nitrates from the zinc coordination sphere is observed when the reaction between L(1) excess and the zinc salt was carried out in hydrothermal conditions. The metal ion type is also determining structure and stoichiometry: the reaction of L(2) with CdCl(2) gave the 2:1 adduct [CdCl(2)(L(2))(2)] 11 where both chlorides complete the coordination sphere of the six-coordinate cadmium center; on the other hand from the reaction of L(1) with CdBr(2) the polynuclear [CdBr(2)(L(1))](n) 12 is obtained, the Br(-) anion acting as bridging ligands in a six-coordinate cadmium coordination environment. The reaction of L(1) and L(2) with HgX(2) (X = Cl, I, SCN) is also dependent on the reaction conditions and the nature of X, two different types of adducts being formed [HgX(L)] (14: L = L(1), 16, 17: L = L(1) or L(2), X = I, 19: L = L(2), X = SCN) and [HgX(L)(2)] (15: L = L(2), X = Cl, 18: L = L(1), X = SCN). The X-ray diffraction analyses of compounds 1, 2, 4, 5, 7, 8, 10-12, 14, 15, and 19 are also reported. The variations of the coordination geometry parameters in the complexes are compared and discussed.     

A novel series of materials composed of arrays of vanadium oxide container molecules, [V18O42(X)] (X = H2O,Cl-, Br-): synthesis and characterization of [M2(H2N(CH2)2NH2)5][(M(H2N(CH2)2NH2)2]2V18O42(X)]. 9H2O (M = Zn,Cd)

The synthesis and characterization of the novel systems [Zn(2)(H(2)N(CH(2))(2)NH(2))(5)][(Zn(H(2)N(CH(2))(2)NH(2))(2))(2)V(18)O(42)(H(2)O)].9H(2)O (1), [Cd(2)(H(2)N(CH(2))(2)NH(2))(5)][(Cd(H(2)N(CH(2))(2)NH(2))(2))(2)V(18)O(42)(Br)].9H(2)O (2), and [Zn(2)(H(2)N(CH(2))(2)NH(2))(5)][(Zn(H(2)N(CH(2))(2)NH(2))(2))(2)V(18)O(42)(Cl)].9H(2)O (3) have been described. These materials represent a new class of solids that have been prepared by combining conventional coordination compounds with spherical polyoxovanadate clusters. The isomorphous structures of these hybrid solids consist of two-dimensional arrays of container cluster molecules [V(18)O(42)(X)] (X = H(2)O, Br-, Cl-) interlinked by the transition metal complex moieties [M(H(2)N(CH(2))(2)NH(2))(2)] (M = Zn, Cd). These compounds contain an unprecedented complex cation, [M(2)(H(2)N(CH(2))(2)NH(2))(5)](4+). Crystal data for 1: C(9)H(46)N(9)O(26)V(9)Zn(2), monoclinic space group P2(1)/m (No. 11), a = 12.3723(7) A, b = 20.9837(11) A, c = 15.8379(8) A, beta = 97.3320(10) degrees, Z = 4.     

Unusual syntheses, structures, and electronic properties of compounds containing ternary, T3-type supertetrahedral M/Sn/S anions [M5Sn(mu3-S)4(SnS4)4](10- (M = Zn, Co)

A recently discovered series of quaternary compounds of the general type [K(m)(ROH)(n)()][M(x)Sn(y)()Se(z)] (R = H, Me), containing ternary anions with [SnSe(4)](4-)-coordinated transition metal centers (M = Co, Mn, Zn, Cd, Hg) has now been extended by the synthesis and characterization of the two ortho-thiostannate-coordinated species, [Na(10)(H(2)O)(32)][M(5)Sn(mu(3)-S)(4)(SnS(4))(4)].2H(2)O (M = Zn (1), Co (2)). The central structural motifs of compounds 1 and 2 are highly charged [M(5)Sn(mu(3)-S)(4)(SnS(4))(4)](10-) anions, being the first T3-type supertetrahedral ternary anions reported to date. The exposure of single crystals of 2 to a dynamic vacuum for several hours resulted in the reversible formation of a partially dehydrated, but still monocrystalline material of the composition [Na(10)(H(2)O)(6)][Co(5)Sn(mu(3)-S)(4)(SnS(4))(4)] (3). The loss of 28 of the 34 water molecules only slightly affects the internal structure of the ternary anion in 3 and leads to a significant compacting of the crystal structure with closer linkage of the [Co(5)Sn(5)S(20)](10-) cluster units via the Na(+) cations. Magnetic measurements on 3 show that the ground state of the Co/Sn/S cluster is S = 1/2, indicating a significant antiferromagnetic coupling between the Co centers, which has also been rationalized by DFT investigations of the electronic situation in the ternary subunits of 1-3.